This invention relates to chemical lasers and, more particularly, to a system for generating molecular oxygen in the excited singlet-delta electronic state.
The amplification of coherent electromagnetic radiation in the visible and infrared spectrum of the optical frequency range, generally referred to as lasing action, has generated considerable interest in various electronic disciplines. A laser produces a beam of coherent electromagnetic radiation having a well defined frequency in the optical range and, in addition to the visible and infrared spectrum, includes the ultraviolet spectrum. The coherence of the laser beam sets it apart and makes it distinguishable from ordinary light beams which are incoherent. The laser beam has a very small divergence and therefore, is highly directional. Also, its coherence feature makes it especially useful for communication and navigation applications since its frequencies are many times higher than radio frequencies thus permitting it to carry many times more information than a radio beam.
A number of systems and devices have been developed for producing a lasing action for use in heating, navigation and communication applications. These devices employ an optically active media, which may be either solid, liquid or gaseous, from which the laser beam is extracted by means of a phenomena called population inversion. The active media possesses unstable high energy states which can release photons as they decay to lower energy states. Also, there must be a greater number of higher energy states than lower energy states in the media.
Flowing gas systems are preferred for high energy laser devices and the requisite population inversion is accomplished by means of a chemical reaction. These so-called chemical lasers induce the lasing action by mixing a lasing substance, or optically active media with an electronically excited energizing gas and then directing a flow of the gaseous mixture into an optical laser cavity where the lasing action is generated. The lasing media and the electronically excited gas react chemically to provide the necessary population inversion and lifetime required to create the lasing action. For example, the photon emission necessary for laser operation can be achieved by the resonant transfer of energy, through collisions, between an energizing substance such as excited nitrogen and a lasing substance such as carbon dioxide. Other chemical lasing systems utilize hydrogen and fluorine to achieve a lasing action as well as mixtures of helium and carbon dioxide and mixtures of helium, nitrogen and carbon dioxide.
The chemical laser systems have proven to be very useful for a number of applications and considerable interest in their development has evolved, especially in the area of materials supply. The attendant problems associated with preparing, storing, maintaining and delivering the requisite reactant gases has hindered the application of chemical lasers for military and airborne applications.
In attempting to find solutions to the problems of providing simple, efficient and dependable sources of electronically excited energizing gases for chemical lasers, it has been found that a chemical reaction between chlorine gas and a basic solution of hydrogen perioxide will generate a stream of molecular oxygen in the excited singlet-delta electronic state. The excited oxygen can then be added to a suitable lasing medium and the mixture passed through an optical resonator to bring about a lasing action.